[nareck]

I don't have a multimeter currently. And I haven't measured the resistances of the harness.

Currently it's the first time in the last couple of years that I was struggling with this problem that I can see something that is off: the state (faded colors) of the wires going into the connector. It may sound weird but I am excited about it. I have made some close up videos of the wires. I don't know if this is a big deal, you guys are more experienced, I'd like to hear your opinion. Also hard to decide from where to cut the old wires.

M52tu MDK Wires

youtube.com

 

[NZ00Z3]

Yes the wires are dirty on the outside. That does not make them damaged.

Spray a lot of contact cleaner into the back of the MDK harness plug and give it a light scrub. That is where the wires come together and any pollution/salt build up can cause a short between cores. Especially pin groups 6, 7 and 8 plus 3, 4 and 5.

Had another look at your fault codes. Looks like there is a short in the power supply to the Potentiometer 1 group. Suggest you do the following tests.

• Make sure you have a fully charged battery.
• With the MDK removed, Turn the key to position 2, do not start the engine.
• Test for 5V on harness MDK connector pins 1 and 7.
• Test for 5V on harness MDK connector pins 2 and 4.
• Turn the key off.

If you have 5V at both sets of pins, then connect the MDK to the harness and redo the above tests. This time back-probing the MDK harness connector.

Report back with the results.

 

[nareck]

Yes the wires are dirty on the outside. That does not make them damaged.

That's not dirt. I have sprayed/cleaned them with contact cleaner before recording the videos. It looks like they have been effected by heat. If you look at the bright wire colors near the pin, for example the green, they are ok but moving towards the other direction it becomes yellowish but the wire itself is clean.

 

[nareck]

Test for 5V on harness MDK connector pins 1 and 7.

How to position multimeter's pins? (Sorry, I have never measured voltage).

BTW I have noticed that wires for 9 and 10 pins are a bit thicker than the rest.

 

[NZ00Z3]

The pin numbers relate to the numbers next to the individual connectors (pins) on the MDK harness connector. A good light/flashlight will let you see them.

With the MDK removed. You can place the multi-meter probes onto the connector side that goes in to the the MDK. As the probes will have a voltage on them, do not let them touch. They will spark and likely blow a fuse somewhere.

With the MDK installed. You need to back probe the wires side if the MDK harness connector. Back-probing is where you use a small conductive item to extent the connection. I use a bent straight metal paper clip. This give a long wire to put into the connector by the wire and still have a bent bit at the end to easily grip and connect to the meter probes. Once again. As the probes will have a voltage on them, do not let them touch. They will spark and likely blow a fuse somewhere.

 

[nareck]

I am sorry for silence. Just finished the soldering. Boy, it took me a ling time... Haven't put back MDK and other stuff yet.

 

[nareck]

I have messed up something: after cleaning error codes with INPA new errors appear without even staring the car, just key in 2nd position. Attaching those errors. Can anyone give me a hint what can be the reason?

I've started the car, worked for a minute or so smoothly then went into limp mode.

 

[NZ00Z3]

The 2 "activation idle adjuster" codes are for the Idle control Valve. Have you remembered to plug it back in?

 

[nareck]

Will check again. I remember connecting the connector, is it possible to connect it in a wrong way?

 

[NZ00Z3]

Did you take the Idle control valve out and give it a clean? It should rattle easily when shaken.

The Idle control valve connector can only go on one way.

When installing the MDK, the accelerator cable should be just slack with the MDK closed.

 

[nareck]

No, I haven't taken out the ICV, only plugged out/in its connector.

 

[NZ00Z3]

If checking the ICV plug does not solve your problem, then take the ICV out and give it a clean with carb cleaner or brake cleaner. Lots of black will come out of it.

 

[nareck]

I have cleaned it not so long ago, and the car was not being used afterwards. It must be something with the wiring as I don't even start the car and those errors appear.

 

[nareck]

@NZ00Z3 you were right, the ICV plug was not clipped in its place.
ICV errors disappeared but MDK errors were coming back, even without staring the engine 169 error from the last screenshot reappeared. After starting the engine those 2 appeared: 118 and 173...

 

[nareck]

Then as an act of desperation I did the ritual of cleaning error codes again, and no error was coming back for a while (15 minutes with multiple engine starts).
Then started the engine again, all good, and as I was refreshing INPA's error screen a new one appeared: 208 revolution control not okay, EWS. Engine is still running fine even after switching off and on. Didn't move/drive the car, tomorrow probably will manage to do that. But what should I do with that EWS error?

 

[NZ00Z3]

Sounds like you are closely getting all of this sorted. Well done.

Code 208 is saying that the EWS is not getting the rpm signal from the DME. Clear the code and see if it comes back.

If you are still getting the throttle poti plausibility codes, try a MDK adaptations reset.

Using INPA to delete the adaptations

• Switch off the ignition for 30 seconds.
• Turn on the ignition to position 2. Do not start the engine.
• Delete DME fault code memory and adaptations.
• Press the accelerator pedal to wide open throttle (WOT) four times.
• Remember that this procedure has deleted the engine adaptations, so don’t get surprised if the engine’s idle is a little off when you first start the car. It will correct itself with the first test drive.

 

[nareck]

Switch off the ignition for 30 seconds

If the ignition was switched off for days without the battery in the car am I good or should I switch on the ignition after battery attachment just once?
I know that this might sound as a redundant question, just want to be sure.

 

[NZ00Z3]

My Z3's live with the battery disconnected and a trickle charger on the battery. They do not have any problems when I re-connect them and take them out for a run. One is a M52TUB20 with MS42 DME, similar to your car.

 

[nareck]

Today was a good day too (no MDK issues). Took the car for a 20 minute ride with a couple of stops, runs smoothly. But that EWS error keeps coming back. I remember during soldering days once I switched off the battery while the key was in the car (not switched on state). They say that's not good for EWS but if the key is in switched on position. I don't know what to do now.
In the SES_test_proceedure.pdf document there's a whole procedure for troubleshooting (Vehicle immobilization, test module B1214_M0EWS) but it has some unknown termins.
I'd appreciate any advice.
When this error is resolved and some time is passed with multiple successful rides then we can consider one more MDK success story.

 

[NZ00Z3]

Wow, now that's some file you have posted. Lots of really good information in there. Where did you find it?

I have had a read of B1214_M0EWS. It is saying that you have a communications problem between the engine DME and the EWS. The EWS is not receiving the speed monitoring signal. The communication is via K-Bus, which is a type of CAN-Bus.

Have you had the instrument cluster out recently? If so check that the connections are tight.

This is a good resource on fault finding K-Bus: BMW E46 K-Bus Troubleshooting